They found that the number of 16-24s moving away from traditional sexual intercourse had doubled, with experts claiming that the easy access to internet pornography was partly behind the rise.

Dr Ruth Lewis, who conducted the work while at the LSHTM said: “At a time when much sex and relationships education is being updated, keeping pace with current trends in sexual practices is crucial so that curricula are tailored to the realities of young people's experiences.

"By shedding light on when some young people are having sex and what kinds of sex they are having, our study highlights the need for accurate sex and relationships education that provides opportunities to discuss consent and safety in relation to a range of sexual practices.”

However, the researchers found that the median age for first sexual experiences has not changed much in recent decades.

In the most recent survey, the median age of reported first sexual experience among men and women born between 1990 and 1996 was 14. The median age for losing virginity is now 16 across for both men and women.

In the 1950s it was 20 for women and 19 for men.

Kaye Wellings, Professor of Sexual and Reproductive Health at LSHTM, said: "The changes in practices we see here are consistent with the widening of other aspects of young people's sexual experience, and are perhaps not surprising given the rapidly changing social context and the ever-increasing number of influences on sexual behaviour.

"It is important to keep up to date with trends in sexual lifestyles to help young people safeguard their health and increase their well being."